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2023.11.09 Staff Report.pdf November 9 2023 Staff Report To: Conservation Commission From: Sarah LaValley RE: Staff Report, November 9 2023 Commission Meeting 5:30 PM, continuation. Notice of Intent for septic system replacement within bordering land subject to flooding (Connecticut River). Jonathan Fogelson. 128 Cross Path Road. Map ID 32-014 Application Overview: The application proposes construction of a septic system within BLSF to accommodate additional bedrooms yet to be constructed. The Commission continued the hearing to allow the applicant to obtain a survey with elevation data. To achieve required separation from groundwater, the system will be mounded, and create a 9,982 cubic foot mound between the 117-120.5’ elevations. Compensatory storage is proposed to be created by demolition of structures at the 118’ elevation, and removal of field material at 117’ for the remainder. Consistency with the WPA and Northampton Wetlands Ordinance, Staff Recommendations: The Commission will need to be able to find that the work meets the standard that: “Compensatory storage shall mean a volume not previously used for flood storage and shall be incrementally equal to the theoretical volume of flood water at each elevation, up to and including the 100-year flood elevation, which would be displaced by the proposed project.” Removal of volume at only one incremental 1 foot elevation does not actually comply with the performance standards, though the Commission has allowed storage at lower elevations in some cases. The comp storage table does not appear to accurately represent full elevations (ie, homestead demo only shows storage at the 118’ elevation) If the Commission can find through additional materials presented that the work will not contribute to extent and level of floods, an Order of Conditions can be issued, with standard conditions, and documentation of fill removed. The compensatory storage area will need to be created prior to the septic work. If additional house footprint expansion is proposed, that will require additional review. If an elevation certificate is required by the Building Department, the Commission must be provided a copy. November 9 2023 Staff Report 2 5:35 PM Request for Determination of Applicability to determine if utility pole installation in buffer zone is subject to the Wetlands Protection Act or Northampton Wetlands Ordinance. MassElectric Company. Bradford St Right-of-way Application Overview: The application proposes installation of one new utility pole, two replacement poles, and associated anchors and guy wires within buffer zone; in the Protected Zone. Tree trimming ‘as necessary’ and removal of one tree is specified but no additional details are provided. Consistency with the WPA and Northampton Wetlands Ordinance, Staff Recommendations: Replacement tree planting should be discussed. The Commission can also discuss the materials with which the utility pole is planned to be treated, as this can impact wetland soil health and affect soil microinvertebrates. An untreated pole should be considered. If the Commission can find that the work will not impact the resource area, a negative determination, box 3, could be issued. 5:45 PM Request for Determination of Applicability to determine if septic system installation in riverfront (Mill River) is subject to the Wetlands Protection Act or Northampton Wetlands Ordinance. Abbot Gray Realty Trust. 123 Meadow Street, Map ID 22B-066 Application Overview: The application proposes installation of a septic system within riverfront, buffer zone, and bordering land subject to flooding. The work was already completed without permits. Consistency with the WPA and Northampton Wetlands Ordinance, Staff Recommendations: The Commission should evaluate the work as if it were not already completed; no applicable performance standards can be waived, as the work was a violation. The Commission should discuss siting if the system within resource, and whether any alternative locations were evaluated. While the application indicates that the work is exempt from riverfront area performance standards, the septic system installed is a substantial enlargement and as such does not qualify for an exemption. Since the work is already completed, it is . The application indicates that the site is already revegetated with grass and . If this was the prior site condition, and no changes in elevation that would alter flood storage have been included, the work may be appropriate for a negative determination by checking box 2, noting that no boundaries are confirmed. If vegetation removal or topographical changes were included, a notice of intent may be required. November 9 2023 Staff Report 3 6:00 PM Notice of Intent for construction of a 4-bay garage, driveway, and stormwater management. DA Sullivan & Sons, 504 Easthampton Road. Map IDs 44- 136 and 117. DEP File 246-776 Application Overview: The application proposes construction of a 3,680 sf garage, paving and parking area. A portion of the area to be developed is currently gravel, and the remainder is mown lawn. A stormwater system, to include an infiltration basin and water quality swale is also proposed. Though not shown on plans, a subsurface tight tank will accept drainage from the garage so that oil does not enter the stormwater system. Site Plan review by the Planning Board will also be required. Removal of one significant tree is proposed. DEP Comments: [1] One cannot model stormwater without confirming actual soil type. Per Volume 3 Chapter 1 of the stormwater handbook, a Competent Soils Professional conducts a site visit to verify soil conditions on the site. Please see Table 2.3.1. Then, a statement must always be included in the stormwater report as to whether or not the competent soils professional has found that the soils actually found on site are consistent, or not, with the NRCS Soil Survey. Staff note: A test pit was conducted, and was added to revised plans and stormwater report. [2] The stormwater management system fails to comply with the stormwater standards. There is no BMP that is called an infiltration swale. There is a water quality swale, that is a conveyance BMP, that receives 70% TSS removal if combined with a sediment forebay All stormwater BMP's must be designed, constructed, operated and maintained per the Stormwater Handbook, Volume 2, Chapter 2, which does not appear to be the case. The simplest thing to do is to cut and paste the relevant pages of the Handbook into the Stormwater Report and use that to describe compliance. If an infiltration basin is proposed, it must have pretreatment and soils and depth to seasonal high ground water must be known. See Volume 1 Chapter 1 of the Handbook for more information as well as Vol. 2 Chapter 2. Staff note: A revised plan was submitted that addresses this comment. DPW had only minor comments on the stormwater system, incorporated below [3] As a reminder, a log book on maintenance of the stormwater system must be kept and made available for commission or MassDEP review upon request. This item should be discussed at the hearing as this requirement is frequently not met by an owner. Staff note: This could be added as a condition [4] Per 310 CMR 10.53(1 ), where a Buffer Zone has already been developed, the Issuing Authority may consider the extent of existing development in its review of subsequent proposed work and, where prior development is extensive, may consider measures such as the restoration of natural vegetation adjacent to a Resource Area to protect the interest of M.G.L. c. 131, § 40. Staff note: Staff concurs, while the resource area is located on an adjacent property, improvement of the site is not proposed Consistency with the WPA and Northampton Wetlands Ordinance, Staff Recommendations: Staff have no concerns with the accuracy of the resource area boundary. The work is a buffer zone only project, but must also comply with the stormwater standards and the Wetlands Ordinance. Most of the Ordinance standards do not apply since this is located in the OI November 9 2023 Staff Report 4 zone. However, a reduced 10-foot setback is only provided for projects where development includes mitigation measures that will improve the existing condition of the wetlands or adjacent upland. This standard does not appear to be met. The plans indicate knotweed removal. How will this be achieved? A detailed multi-year plan is necessary, including followup and replacement plantings. It is not clear how roof runoff will be handled The no-disturb area should be marked, it is already being used for storage. The Commission should note that the knotweed extends beyond the property boundary, and is not proposed to be removed from the resource area as part of the project. The offsite wetland also includes degraded area and dumped materials that would be ideal for restoration. A detailed planting plan for the full site, including the planted stormwater bed, that also specifies how vegetated areas will be stabilized is necessary The drainage calculations assume that 100% of the impervious (roof and paved) in the area analyzed up to Easthampton Rd will flow to the proposed water quality swale and infiltration basin. The plans show an existing drop inlet at the existing loading dock near the front of the site but does not describe where this goes. The proposed grading plan does not make it clear how flows from the front of the site will reach the infiltration basin--see attached photo. Additional grading or structural changes may be necessary to get all these flows to the infiltration basin. This may not be an issue in meeting stormwater standards and the calculations could be changed to not include the front areas to eliminate this question. If these issues have not been addressed, continue the hearing until the December 14 meeting. Facing east along southern property boundary. Knotweed proposed to be removed from site is on the right of the photo. The knotweed visible in the rear is on an adjacent parcel November 9 2023 Staff Report 5 Facing east from rear property line at wetland boundary. Area proposed for garage and stormwater system. Tree in center of photo proposed to be removed.